Luminescent laser hosts

Leverenz HW (1968) An Introduction to Luminescence of Solids. Dover Publications, New York Louis-Achille V, DeWindt L, Defranceschi M (2000) Electronic structure of minerals The apatite group as a relevant example. Inti J Quantum Chem. 77 991-1006 Loutts GB, Hong P, Chai BHT (1994) Comparison of neodymium laser hosts based on a fluoro-apatite structure. Mater Res Soc 1994 45-49... 

Nonmetallic inorganic materials are widely used for optical purposes lenses, pigments, interference filters, laser hosts, luminescent coatings, displays, solar cells, fiber optics, lamp bulbs, and tubes. For optical applications use is made of the refractory index, light absorption, luminescence, and nonlinear optical behavior of materials. These are intrinsic but may depend on the concentration of impurities. Refraction index and optical absorptivity in insulators are atomic properties and are only indirectly related to the structure, but the structure affects the selection rules and the term splitting in the atomic chromophores. The coordination number determines the intensity and wavelength of absorption and... 

The spectra of the green laser-induced luminescence represented in Fig. 4.4a, together with their decay time, also allows its association with These luminescence spectra strongly differ from the spectral parameters of all known uranyl minerals. For this reason it is not possible to connect this type of green luminescence with finely dissipated uranyl phases. On the other hand, this luminescence is very similar in such different host minerals as sedimentary apatites, opalites, chalcedony, chert, quartz and barites. Luminescence independence from the minerals structure evidences that it may be connected with uranyl adsorption on the minerals surface, supposedly in the form of (UO2 X nH20)2+. 

According to spectral-kinetic parameters, the optimal conditions of luminescence excitation and detection, so called selection window (SW) parameters, were calculated in the following way. At optimal for the useful component excitation, the liuninescence spectra, decay time and intensity were determined for this mineral and for the host rock. After that, on the personal computer was calculated the proportion between useful and background signals for the full spectral region for each 50 ns after laser impulse. For calculation the spectral band was simulated by the normal distribution and the decay curve by the mono-exponential function. The useful intensity was multiplied by the weight coefficient, which corresponds to the concentration at which this component must be detected. 

Vol. 34. Neutron Activation Analysis. By D. De Soete, R. Gijbels, and J. Hoste Vol. 35 Laser Raman Spectroscopy. By Marvin C. Tobin Vol. 36 Emission Spectrochemical Analysis. By Morris Slavin Vol. 37 Analytical Chemistry of Phosphorus Compounds. Edited by M. Halmann Vol. 38 Luminescence Spectrometry in Analytical Chemistry. By J. D.Winefordner, S. G. Schulman, and T. C. O Haver... 

Within the cross-over region there is more complicated mixing between doublet and quartet states and the luminescence band is broad with additional sub-bands (11). Because of the importance of ruby lasers and related Cr3+ activated systems, the physics of the doublet-quartet transition has been worked out in considerable detail as has the mechanism of non-radiative transfer and the temperature dependence of the luminescence(12). Although the Cr3+ narrow band emission is essentially independent of crystal field and thus of site size and symmetry, the energy of the doublet levels does depend on Racah parameters B and C. The B and C parameters are dependent on the covalency of the metal-ligand bond and thus there is some variability in the Cr3+ emission from host to host. 

Although the conductivity of the trivalent-ion / ""-aluminas is too low for solid electrolyte applications (e g. batteries, sensors), they have potential use in optics, phosphors, and lasers because they can serve as single crystal or powder hosts for the optically active lanthanide ions. For example, Eu +-/3""-alumina emits red luminescence when excited by UV rays. A Nd +-/3""-alumina single crystal shows luminescent... 

Main group oxides with three-dimensional stmctures or transition metal oxides with d° or d ° configurations are wideband gap materials and are colorless when pure. As such they may serve as transparent optical materials or hosts for such applications as lasers or luminescent materials when properly doped. Others that lack a center of symmetry may have ferroelectric or ferroic properties that make them useful for a variety of device applications. Some of these may have nonlinear optical properties so important to modem communication networks (see Sections 6.3 and 6.5 and see Luminescence and see Ferroelectricity). 

Neodymium. Neodymium can be present in relatively high concentrations in fluorapatites. Gaft et al. (2001a) lists Nd analyses for several natural apatites that are higher than any other REE except Ce, and at a concentration level of about 40% of the Ce value. Nd emission is well into the IR, and it is not sensitized by most of the other REE. Hence, Nd emission is expected to be relatively independent of other impurities, and will not contribute to visible luminescence. However, Nd -doped synthetic apatites are excellent laser materials, due to several physical attributes of the Nd electronic structure in the host lattice. Detailed evaluation of the optical properties of Nd in Ba fluorapatite... 

Using benzophenone (BZP) as probing hosts, laser induced luminescence was employed to get a deeper understanding regarding the mechanism involved... 

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